Abstract
Earlier studies have shown that cardiovascular autonomic regulation is impaired in
untreated or poorly controlled systemic hypertension. The purpose of this double-blind,
randomized parallel trial was to evaluate whether improved blood pressure (BP) control
can reverse this impairment. The study group consisted of 33 patients (age 45 to 63
years) with poor BP control who received randomized metoprolol or enalapril monotherapy.
Baroreflex sensitivity (BRS) was assessed by phenylephrine test and time- and frequency-domain
measurements of heart rate variability (HRV) were analyzed from 24-hour ambulatory
electrocardiographic recordings during monotherapy and after 10 weeks of combination
therapy with metoprolol + felodipine or enalaril + hydrochlorothiazide to lower casual
BP to <140/90 mm Hg. Intensified treatment decreased 24-hour systolic and diastolic
BP from 139 ± 12/86 ± 8 mm Hg to 126 ± 8/80 ± 7 mm Hg (p <0.0001). BRS improved from
6.2 ± 3.2 ms/mm Hg to 8.9 ± 4.1 ms/mm Hg (p <0.0001) and measurements of HRV (e.g.,
SD of all RR intervals from 128 ± 45 ms to 145 ± 46 ms, p <0.001) improved significantly
during the combination therapy. Changes in BRS and HRV were similar in magnitude in
both treatment arms. Mean RR intervals were comparable before and after intensive
antihypertensive therapy (850 ± 124 ms vs 937 ± 279 ms, p = NS). These data indicate
that adequate BP control with modern antihypertensive combination therapy can improve
cardiovascular autonomic function, which may partially explain the reduced cardiac
mortality observed in patients with intensified antihypertensive therapy.
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Article info
Publication history
Published online: August 16, 2004
Accepted:
November 9,
1998
Received in revised form:
November 9,
1998
Received:
September 8,
1998
Footnotes
☆This work was supported by grants from the Finnish Foundation for Cardiovascular Research, Helsinki, Finland, and Astra-Finland, Masala, Finland.
Identification
Copyright
© 1999 Excerpta Medica Inc. Published by Elsevier Inc. All rights reserved.
